6-Azo-5,5&#39;-Dihydroxy-7,7&#39;-Disulfo-2-2&#39; Dinaphthylamine Derivatives

ABSTRACT

The present invention provides 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives, their use as dyes, dyed paper and formulations comprising them.

The present invention refers to6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives, totheir use as dyes, to dyed paper and to formulations comprising them.

Compounds having two 7-amino-3-azo-4-hydroxy-2-naphthalenesulfonic acidunits are common dyes.

DE 196 15 260 A1, for example, describes dyes of the formula

in which two 7-amino-3-azo-4-hydroxy-2-naphthalenesulfonic acid unitsare linked via a urea group.

It is an object of the present invention to provide novel dyes havingtwo 7-amino-3-azo-4-hydroxy-2-naphthalenesulfonic acid units, which canbe used for dyeing natural or synthetic materials, especially paper, andwhich show excellent colour strength, brilliance and substantivity.

This object is solved by the6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivativesaccording to claims 1-3 by aqueous and solid formulations thereofaccording to claims 7 and 8 and by paper according to claim 6.

The 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivativesof the present invention have formula

in whichR¹ represents

-   -   in which    -   a is 1-4    -   n is 0 or 1,    -   R³ represents hydrogen, C₁₋₄-alkyl, C₃₋₆-cycloalkyl, aralkyl,        phenyl, C₁₋₄-alkoxy, sulfo, hydroxy, nitro, halogen,        C₁₋₄-alkylcarbonyl, carboxy, carbamoyl, C₁₋₄-alkoxycarbonyl,        C₁₋₄-alkylaminocarbonyl, cyano, amino, ureido or NHCOC₁₋₄-alkyl,        whereby C₁₋₄-alkyl and C₁₋₄-alkoxy may be substituted with        hydroxy or C₁₋₄-alkoxy, and phenyl may be substituted with        C₁₋₄-alkyl, C₁₋₄-alkoxy, sulfo, hydroxy, nitro, halogen or        carboxy, and    -   A¹ if n is 1 is selected from the group consisting of

-   -   in which    -   m, p and q are identical or different, and are 0, 1 or 2,    -   R⁵ and R⁶ are identical or different and represent hydrogen,        C₁₋₄-alkyl, C₃₋₆-cycloalkyl, aralkyl, phenyl, C₁₋₄-alkoxy,        sulfo, hydroxy, nitro, halogen, C₁₋₄-alkylcarbonyl, carboxy,        carbamoyl, C₁₋₄-alkoxycarbonyl, C₁₋₄-alkylaminocarbonyl, cyano,        amino, ureido or NHCOC₁₋₄-alkyl, whereby C₁₋₄-alkyl and        C₁₋₄-alkoxy may be substituted with hydroxy or C₁₋₄-alkoxy, and        phenyl may be substituted with C₁₋₄-alkyl, C₁₋₄-alkoxy, sulfo,        hydroxy, nitro, halogen or carboxy, and    -   A¹ if n is 0 is

-   -   R² represents H or

-   -   in which    -   w is 0 or 1,    -   R⁷ and R⁸ are identical or different and represent hydrogen,        C₁₋₄-alkyl, C₃₋₆-cycloalkyl, aralkyl, phenyl, C₁₋₄-alkoxy,        sulfo, hydroxy, nitro, halogen, C₁₋₄-alkylcarbonyl, carboxy,        carbamoyl, C₁₋₄-alkoxycarbonyl, C₁₋₄-alkylaminocarbonyl, cyano,        amino, ureido or NHCOC₁₋₄-alkyl, whereby C₁₋₄-alkyl and        C₁₋₄-alkoxy may be substituted with hydroxy or C₁₋₄-alkoxy, and        phenyl may be substituted with C₁₋₄-alkyl, C₁₋₄-alkoxy, sulfo,        hydroxy, nitro, halogen or carboxy, and    -   A² represents either A¹, whereby A¹ has the meaning as indicated        for the 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine        derivatives 1 of the present invention, or A² represents

-   -   in which    -   R⁹ and R¹⁰ are identical or different and represent hydrogen,        C₁₋₄-alkyl, C₁₋₄-alkoxy, sulfo, hydroxy, nitro or carboxy,    -   E represents sulfur or NH.

C₁₋₄-Alkyl is methyl, ethyl, propyl, isopropyl, butyl, sec-butyl,tert-butyl or isobutyl. C₁₋₄-Alkoxy is methoxy, ethoxy, propoxy,isopropoxy, butoxy, sec-butoxy, tert-butoxy or isobutoxy.C₃₋₆-Cycloalkyl is cyclopropy, cyclobutyl, cyclopentyl or cyclohexyl.Aralkyl can be benzyl or 2-phenylethyl. C₁₋₄-Alkoxy is methoxy, ethoxy,propoxy, isopropoxy, butoxy, sec-butoxy, tert-butoxy or isobutoxy.Halogen can be fluorine, bromine, chlorine or iodine.

Preferences:

R³ preferably represent hydrogen, C₁₋₄-alkyl, C₁₋₄-alkoxy, sulfo,hydroxy, nitro or carboxy, whereby C₁₋₄-alkyl and C₁₋₄-alkoxy may besubstituted with hydroxy.

More preferably R³ represents C₁₋₄-alkyl, e.g. methyl.

R⁵ and R⁶ are identical or different and represent hydrogen, C₁₋₄-alkyl,C₁₋₄-alkoxy, hydroxy, nitro or carboxy, whereby C₁₋₄-alkyl andC₁₋₄-alkoxy may be substituted with hydroxy.

More preferably R⁵ and R⁶ are identical or different and representhydrogen, C₁₋₄-alkyl, nitro or hydroxy.

R⁷ and R⁸ are identical or different and represent hydrogen, C₁₋₄-alkyl,C₁₋₄-alkoxy, hydroxy, nitro or carboxy, whereby C₁₋₄-alkyl andC₁₋₄-alkoxy may be substituted with hydroxy.

More preferably R⁷ is C₁₋₄-alkyl, which may be substituted with hydroxyand R³ is C₁₋₄-alkyl.

Even more preferred are 6-azo-7-amino-4-hydroxy-2-naphthalenesulfonicacid derivatives of formula 1 wherein

R¹ represents

in whichn is 0 or 1,A¹ if n is 1 is selected from the group consisting of

in whichm is 1 or 2,p is 0 or 1,R⁵ is hydrogen, methyl or nitro,R⁶ is hydrogen or hydroxy, andR² represents H or

in whichw is 0 or 1,A² represents either A¹ as defined above or is selected from the groupconsisting of

Most preferred are6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives offormula 1 wherein

n is 0 and R¹ and R² are both

Also part of the invention, is the use of the6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-di-naphthylamine derivatives 1 ofthe present invention as a dye for dyeing natural or synthetic materialssuch as paper, cellulose, polyamide, leather or glass fibres. Preferablythe 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives 1are used for dyeing paper.

Paper dyed with 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylaminederivatives 1 is also part of the invention.

The 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives 1can be applied to the materials, preferably to paper, in the form ofaqueous or solid formulations.

The aqueous and solid formulations comprising6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-di-naphthylamine derivatives 1are also part of the invention.

The solid formulations comprising6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives 1 canbe powders or granulate materials, and may include auxiliaries. Examplesof auxiliaries are solubilizers such as urea, extenders such as dextrin,Glauber salt or sodium chloride, sequestrants such as tetrasodiumphosphate, and also dispersants and dust-proofing agents.

The aqueous formulations comprising6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives 1 mayalso include auxiliaries. Examples of auxiliaries used for aqueousformulations are solubilizers such as ε-caprolactam or urea, and organicsolvents such as glycols, polyethylene or polypropylene glycols,dimethyl sulphoxide, N-methylpyrrolidone, acetamide, alkanolamines orpolyglycolamines. Further auxiliaries used in aqueous formulations areviscosity modifiers, antifoaming agents or dispersing agents.

Preferably, the aqueous formulations are aqueous solutions whichcomprise from 5 to 30% by weight6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives 1based on the weight of the solution. Preferably, these concentratedaqueous solutions also contain a low level of inorganic salts, which maybe achieved by known methods, for example by reverse osmosis.

The 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives 1are dyes, which show excellent colour strength, luminance andsubstantivity.

Due to the —O—[(CH)₂]_(a)—OH group the compounds are less carcinogen.

EXAMPLES Examples 1 Preparation of

46% (w/v) sodium nitrite (75.8 mL) is added to a suspension of 49.7%(w/w)4-[(4-amino-5-hydroxyethoxy-o-tolyl)azo]-5-hydroxynaphthalene-2,7-disulphonicacid (123 g) in desalinated water (600 mL) at room temperature. Theobtained solution is cooled to 10° C. and added to a solution ofconcentrated HCL (195.5 mL) in desalinated water (200 mL) within 90minutes. The reaction mixture is stirred for further 60 minutes at roomtemperature. Excess nitrite is destroyed by addition of sulfamic acid.

The obtained solution is added to a suspension of5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthyl-amine (91.24% (w/w), 92 g)in desalinated water (300 mL) within 90 minutes at room temperature andat pH 9.0. The reaction mixture is stirred overnight at roomtemperature.

NaOH (50% (w/v), 167 mL) is added to the solution. The reaction mixtureis warmed to 90° C. for 2 hours. Then, the reaction mixture is cooled toroom temperature, and the pH is adjusted to 7.3. Isopropanol (600 mL) isadded at room temperature. The obtained precipitate is filtered anddried in vacuo at 80° C. to yield 152 g=69%

The4-[(4-amino-5-hydroxyethoxy-o-tolyl)azo]-5-hydroxynaphthalene-2,7-disulphonicacid is prepared analogous to Example 3.

Example 2 Preparation of

HCl conc (24.49 mL) is added to a suspension of 95%6-amino-2-naphthalenesulfonic acid (23.5 g) in salinated water (140 mL).46% (w/v) Sodium nitrite (15.16 mL) is added within 20 minutes at 10° C.The mixtures is diluted with salinated water (50 mL) and stirred forfurther 30 minutes.

The obtained solution is added to a suspension of 91.24% (w/w)5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine (25.29 g) indesalinated water (250 mL) within 90 minutes at 10° C. and at pH 8.2.The reaction mixture is warmed to room temperature. Isopropanol (500 mL)is added and the mixture is stirred for 15 minutes. The mixture isfiltrated and the precipitate is dried to yield 37.88 g

Examples 3 Preparation of

HCl conc (24.49 mL) is added to a suspension of 97.2%1-amino-6-naphthalenesulfonic acid (11.41 g) in salinated water (60 mL)at room temperature. 46% (w/v) Sodium nitrite (7.58 mL) is added within30 minutes at 10° C. Excess nitrite is destroyed by addition of sulfamicacid, and the pH is adjusted to 2.1. To this solution was added within10 minutes a solution of 2-(2′-hydroxyethoxy)-5-methylanilin (8.6 g) indesalinated water (50 mL) having a pH of 1.8.

The pH of the mixture is slowly raised to pH 5. The mixture is filteredand the filtrate is treated with 46% 7 w/v) sodium nitrite (7.58 mL),and then added to a solution of HCl conc (24.49 mL) in desalinated water(50 mL). The mixture is stirred for 1 h and excess nitrite is destroyedby addition of sulfamic acid.

This solution is added within 50 minutes to a solution of the compound

in desalinated water (100 mL) at room temperature and pH 8. The mixtureis stirred for 1 hour at room temperature. Isopropanol (500 mL) isadded. The mixture is filtered and the precipitate is dried to yield48.89 g

The above compound is prepared as follows:

46% (w/v) sodium nitrite (75.8 mL) is added to a suspension of 49.7%(w/w)4-[(4-amino-5-methoxy-o-tolyl)azo]-5-hydroxynaphthalene-2,7-disulphonicacid (611.27 g) in desalinated water (600 mL) at room temperature. Theobtained solution is cooled to 10° C. and added to a solution ofconcentrated HCL (195.5 mL) in desalinated water (200 mL) within 90minutes. The reaction mixture is stirred for further 60 minutes at roomtemperature. Excess nitrite is destroyed by addition of sulfamic acid.

The obtained solution is added to a suspension of5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthyl-amine (91.24% (w/w), 252.89g) in desalinated water (300 mL) within 90 minutes at room temperatureand at pH 9.0. The reaction mixture is stirred overnight at roomtemperature.

NaOH (50% (w/v), 167 mL) is added to the solution. The reaction mixtureis warmed to 90° C. for 2 hours. Then, the reaction mixture is cooled toroom temperature, and the pH is adjusted to 7.3. Isopropanol (600 mL) isadded at room temperature. The obtained precipitate is filtered anddried in vacuo at 80° C. to yield 400.2 g

In an analogous manner can be prepared:

Application Examples

Under standard application conditions the paper pulp is stirred with dyeover a defined time period (i.e. 15 min.). If necessary a fixing agent,i.e. Tinofix WSP, will be added. With this pulp a hand sheet will beformed by a sheet former and then dried. The dosage of the dyestuff willbe adjusted to a defined color depth, i.e. (reference depth) RD 0.2.

In case of the comparable urea bridge dye

0.3% of dried material was used. The di-J-acid compound needs only 0.24%to achieve the depth.

The degree of exhaustion was determined after an internal method.

The light fastness is evaluated in a light fastness machine according toISO 105 B02, assessed against blue scale.

The color strength was determined with Helios CFU at reverence depth(RD) 0.2.

The CIELab coordinates and degrees of exhaustion of the dyes aremeasured.

Light C value Example Exhaustion % fastness (brilliancy) Hue 2 96  141.7 342 3 92 2-3 22.6 262 4 91  1+ 27 273 5 93 −2 28.8 282 6 94 −4 23.2259 7 87 −3 19.1 271 8 96 2-3 24.6 278 9 96 −3 25.1 272

The table shows that best brilliance results are obtained using Example2.

1. 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives offormula

in which a is 1-4 n is 0 or 1, R³ represents hydrogen, C₁₋₄-alkyl,C₃₋₄-cycloalkyl, aralkyl, phenyl, C₁₋₄-alkoxy, sulfo, hydroxy, nitro,halogen, C₁₋₄-alkylcarbonyl, carboxy, carbamoyl, C₁₋₄-alkoxy-carbonyl,C₁₋₄-alkylaminocarbonyl, cyano, amino, ureido or NHCOC₁₋₄-alkyl, wherebyC₁₋₄-alkyl and C₁₋₄-alkoxy may be substituted with hydroxy orC₁₋₄-alkoxy, and phenyl may be substituted with C₁₋₄-alkyl, C₁₋₄-alkoxy,sulfo, hydroxy, nitro, halogen or carboxy, and A¹ if n is 1 is selectedfrom the group consisting of

in which m, p and q are identical or different, and are 0, 1 or 2, R⁵and R⁶ are identical or different and represent hydrogen, C₁₋₄-alkyl,C₃₋₄-cycloalkyl, aralkyl, phenyl, C₁₋₄-alkoxy, sulfo, hydroxy, nitro,halogen, C₁₋₄-alkylcarbonyl, carboxy, carbamoyl, C₁₋₄-alkoxycarbonyl,C₁₋₄-alkylaminocarbonyl, cyano, amino, ureido or NHCOC₁₋₄-alkyl, wherebyC₁₋₄-alkyl and C₁₋₄-alkoxy may be substituted with hydroxy orC₁₋₄-alkoxy, and phenyl may be substituted with C₁₋₄-alkyl, C₁₋₄-alkoxy,sulfo, hydroxy, nitro, halogen or carboxy, and A¹ if n is 0 is

R² represents H or

in which w is 0 or 1, R⁷ and R⁸ are identical or different and representhydrogen, C₁₋₄-alkyl, C₃₋₄-cycloalkyl, aralkyl, phenyl, C₁₋₄-alkoxy,sulfo, hydroxy, nitro, halogen, C₁₋₄-alkylcarbonyl, carboxy, carbamoyl,C₁₋₄-alkoxycarbonyl, C₁₋₄-alkylaminocarbonyl, cyano, amino, ureido orNHCOC₁₋₄-alkyl, whereby C₁₋₄-alkyl and C₁₋₄-alkoxy may be substitutedwith hydroxy or C₁₋₄-alkoxy, and phenyl may be substituted withC₁₋₄-alkyl, C₁₋₄-alkoxy, sulfo, hydroxy, nitro, halogen or carboxy, andA² represents either A¹, whereby A¹ has the meaning as indicated for the6-azo-5,5′-di-hydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives 1 ofthe present invention, or A² represents

in which R⁹ and R¹⁰ are identical or different and represent hydrogen,C₁₋₄-alkyl, C₁₋₄-alkoxy, sulfo, hydroxy, nitro or carboxy, E representssulfur or NH.
 2. 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylaminederivatives formula 1 according to claim 1 wherein R¹ represents

in which n is 0 or 1, A¹ if n is 1 is selected from the group consistingof

in which m is 1 or 2, p is 0 or 1, R⁵ is hydrogen, methyl or nitro, R⁶is hydrogen or hydroxy, and R² represents H or

in which w is 0 or 1, A² represents either A¹, whereby A¹ is as definedabove in claim 2, or is selected from the group consisting of


3. 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivatives offormula 1 according to claim 1 wherein n is 0 and R¹ and R² are both


4. A method of dyeing natural or synthetic materials by applying the6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivativesaccording to claim 1 to said materials.
 5. A method for dyeing paper byapplying the 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylaminederivatives according to claim 1 to the paper or paper pulp.
 6. Paperdyed with a 6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylaminederivatives according to claim
 1. 7. An aqueous formulation comprising a6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-di-naphthylamine derivativeaccording to claim
 1. 8. A solid formulation comprising a6-azo-5,5′-dihydroxy-7,7′-disulfo-2,2′-dinaphthylamine derivativeaccording to claim 1.